The present is in Continuation of International Application No. PCT/EP00/06125 of Jun. 30, 2000, which is incorporated herein by reference in its entirety and for all purposes.
The invention relates to a surgical, tubular-shafted instrument comprising a shaft, an operating rod mounted for displacement in the shaft, a handle part for actuating the operating rod and connecting means which connect the handle part and the shaft detachably to one another, wherein the shaft can be secured in an axial direction in an inner sleeve of the handle part by means of a locking member which is displaceable radially in the inner sleeve and dips into a recess of the shaft, the radial outward movement of the locking member being limited by a stop element which can be displaced into a position releasing the radial outward movement of the locking member, and wherein holding means are provided, by means of which the stop element can be fixed in a release position and which can be acted upon by the shaft in such a manner that this fixing can be released due to displacement of the shaft in the inner sleeve.
Such a tubular-shafted instrument is described, for example, in German patent application 198 09 120.6 which is not a prior publication.
In the case of this known tubular-shafted instrument, corresponding connecting means are also provided which connect the operating rod detachably to the handle part.
The object of the invention is to simplify the construction of such an instrument, in particular, with a view to reducing the necessary space required for the connecting means.
This object is accomplished in accordance with the invention, in a tubular-shafted instrument of the type described at the outset, in that the holding means comprise a holding element which is guided for displacement in the handle part outside the inner sleeve.
In the handle part, a corresponding space must be provided outside the inner sleeve in order to arrange the connecting means. In the case of the tubular-shafted instrument described in DE 198 09 120.6, the holding element is guided for displacement within the inner sleeve. This makes it necessary for the inner sleeve to have an interior space which has a greater diameter than the shaft. As a result of the inventive arrangement of the holding element, a space which is, in any case, already present is better utilized and, as a result, the inner sleeve may have smaller dimensions and, therefore, the handle part can be designed, altogether, to be more compact and, in particular, have smaller dimensions.
Furthermore, it is provided in the case of DE 198 09 120.6 for the same locking members to lock the shaft to the handle part in the connection position and fix the release position by means of the holding element. The reason for this is, since not only the shaft but also the holding element is guided within the inner sleeve, that only one radial inwards movement of a locking member can also bring about locking. In the case of the inventive tubular-shafted instrument, the locking of the shaft and the locking of the release position may, on the other hand, be decoupled via the holding element. As a result, space-saving locking mechanisms may be achieved which simplify the construction of an inventive tubular-shafted instrument.
It is particularly advantageous when the holding element is guided for displacement about the inner sleeve. The inner sleeve is then located within the holding element. A displacement of the holding element against the stop element may be brought about in a simple manner in order to thus take care of any fixing of the release position.
It is particularly favorable when the holding element has a coupling element for the shaft which points into the interior of the inner sleeve. In this way, the holding element located outside the inner sleeve can be displaced via the shaft or the holding element can act on the shaft. So that the coupling element can act on the shaft at all, the inner sleeve must have a recess for the coupling element.
It is particularly favorable when the shaft has a guiding recess for the coupling element. The holding element can be guided by means of this guiding recess via the shaft with concerted intermediary of the coupling element, and, on the other hand, the coupling element can guide or secure the shaft accordingly.
It is particularly favorable when the holding element exerts an advancing force on the shaft in a distal direction when the release position of the locking member, which is radially displaceable in the inner sleeve, is reached. The coupling element can then act on the shaft via the recesses. The holding element therefore functions as an ejector for the shaft.
It is particularly advantageous when the shaft can be secured by the coupling element so as to be non-rotatable with respect to the inner sleeve. As a result, it is possible to secure the shaft in the handle part in the connection position in addition to the locking with the locking members. An inventive tubular-shafted instrument can then absorb greater forces and, in particular, greater torques without the shaft becoming detached. However, the locking position may also be achieved more easily since an engagement of the coupling element allows only a linear displacement of the shaft. With a corresponding adjusted alignment between the locking member and the coupling element, it is ensured that the locking member can dip into the recess on the shaft in the connection position.
Favorably, the holding element is guided for displacement surrounding the stop element. As a result, a displacement guidance for the holding element is provided, on the one hand, and, on the other hand, the spatial requirements for this displacement guidance are minimized.
Favorably, a spring for the relative displacement between holding element and stop element is seated between holding element and stop element and is tensioned in the connection position of the shaft. As a result, an automatic displacement of the holding element may be brought about upon the release of the connection position and thus this holding element can be transferred automatically into a position, in which the release position is fixed. As a result, the holding element may also be used advantageously as an ejector for the shaft upon release of the connection position.
It is particularly advantageous when the spring force acts contrary to the direction, in which the stop element can be displaced for the release of the radial outward movement of the locking member. As a result, an automatic fixing of the release position may be brought about in a constructionally simple manner upon the release of the locking position.
In order, in particular, to bring about a simple and secure return of the holding element during the transition from the release position into the locking position, it is advantageous when the spring seated between holding element and stop element is designed and tensioned such that it exerts a smaller spring force in the connection position than a return spring which is seated between stop element and inner sleeve and serves to displace the stop element out of a release position into the connection position when the fixing of the holding element is released. As a result, the first named spring can be tensioned again during the return movement in order to displace the holding element upon release of the connection position.
In a particularly simple embodiment from a constructional point of view, the holding means comprise a locking member which is displaceable radially in the stop element and dips into a recess of the inner sleeve in the release position of the stop element. As a result, the stop element may be secured on the inner sleeve in a simple manner in order to fix the release position for the shaft in this way.
Favorably, the radial outward movement of the locking member is limited in the release position of the stop element by the holding element as stop. An essential function of the holding element is to block the locking member for the fixing of the release position.
Favorably, the holding element has a guiding recess for the locking member, in which this is guided for longitudinal displacement during the displacement of the holding element from its position in the connection position into a position in the release position of the stop element. This guiding recess allows the transition between a defined connection position and a defined release position, wherein the latter can then be fixed.
Favorably, the stop element is designed as a sleeve surrounding the inner sleeve in order to bring about a secure displacement guidance and minimize the spatial requirements.
Furthermore, it is advantageous when the holding element is designed as a sleeve surrounding the stop element in order to likewise bring about a secure displacement guidance and minimize the spatial requirements.
Advantageously, a guide means for the holding element is formed in the handle part in an annular space limited by the stop element. As a result, the spatial requirements can, again, be minimized and a displacement guidance formed in a simple manner.
The further object underlying the invention is to improve a tubular-shafted instrument such that a connection position can be achieved in a simple manner.
This object is accomplished in accordance with the invention, in a tubular-shafted instrument of the type described at the outset, in that the holding means have a holding element with a coupling element, by means of which the shaft can be non-rotatably secured with respect to the inner sleeve due to engagement in a corresponding counterelement of the shaft.
In this way, in addition to the locking member which locks the shaft to the inner sleeve, an additional coupling element independent thereof is provided which secures the shaft non-rotatably. The holding element is already present, in any case, in order to fix the release position. The additional securing against rotation is therefore brought about with the inventive solution by means of minimal constructional resources.
Favorably, the holding element is, for this purpose, guided for displacement outside the inner sleeve in order to keep the spatial requirements to a minimum in this way.
Furthermore, it is advantageous when the counterelement is formed by a recess in the shaft. Such a recess may be produced in a simple manner. As a result of limiting walls of the recess, stop surfaces can be made available which bring about the securing against rotation and, on the other hand, a displacement of the holding element for fixing the release position may also be achieved via such stop surfaces when inserting the shaft into the inner sleeve over the coupling elements.
Additional variations of embodiments of the invention as well as their advantages have already been described above. Reference is made to this description.
The following description of preferred embodiments of the invention serves to explain the invention in greater detail in conjunction with the drawings.